Hepatotoxicity in acute iron poisoning

Although liver injury is a recognized consequence of acute iron poisoning, its description is limited to several case reports. It appears to be dose-related, however, there are published reports of severe iron poisoning without liver injury. The purpose of this study is to examine the hypothesis that this is a dose-related phenomenon and to identify the serum iron concentration of risk for this outcome. The design of this study is a retrospective review of our hospital's experience over 20 years. Extracted data included demographics, time of ingestion, highest serum iron concentration and highest hepatic transaminase activity. Iron poisoning was defined as a serum iron concentration >300 microg/dL (55 micromol/L) within 12 hours of ingestion. Hepatotoxicity was defined as a serum transaminase (either ALT or AST) >150 U/L. Severe hepatotoxicity was defined >1000U/L. Seventy-three patients (1-48 years old) participated in the study and of these patients 60 (47 female) did not have hepatotoxicity. Their serum iron concentrations were 300-704 microg/dL (55-128 micromol/L). Thirteen patients had hepatotoxicity and of these patients, nine had severe liver injury. Severe injury was associated with serum iron concentrations well in excess of 1000 microg/dL (182 micromol/L). Our data support hepatotoxicity due to iron poisoning as a dose-related phenomenon with clinically important cases unlikely with a serum iron concentration of < 700 microg/dL (128 micromol/L) within the first 12 hours. Clinically important hepatotoxicity occurs with values in excess of 1000 microg/dL (182 micromol/L).